Identificação do limiar anaeróbio em indivíduos com diabetes tipo-2 sedentários e fisicamente ativos

Abstract

Objective: To compare anaerobic threshold (AT) intensities determined from blood lactate, blood glucose and ventilatory responses among sedentary (SD) and physically active (AD) type-2 diabetics and active non-diabetics (AND), and to correlate metabolic, hemodynamic and body composition variables with the AT. Method: The SD (n= 9, 56.7 ± 11.9 years), AD (n= 9, 50.6 ± 12.7 years) and AND (n= 10, 48.1 ± 10.8 years) groups performed a cycle ergometer test with increases of 15 watts every three minutes until exhaustion. Heart rate, arterial pressure, perceived exertion, blood lactate, blood glucose and ventilatory variables were measured during the last 20 seconds of each incremental stage, to determine the lactate, ventilatory and glucose thresholds. Results: The AT intensities identified by the different methods did not differ from each other (p> 0.05). However, the absolute intensities were lower for SD than for the active groups (p< 0.05). No differences in intensity were found between the groups in relation to maximum oxygen consumption (%VO 2 peak) and maximum power (%Ppeak) at which the AT was observed. There was a significant correlation between AT and percentage fat (r= -0.52), and there was a trend towards correlation between AT and ambulatory blood glucose (r= -0.33). The hemodynamic variables did not show any correlations with AT. Conclusion: The AT was identified by means of the techniques studied, among type 2 diabetics and non-diabetics. Despite the differences between the groups with regard to absolute intensities (Watts), diabetes did not appear to influence the relative intensities at which the AT was observed. The AT presented a correlation with body composition and a trend towards correlation with ambulatory blood glucose, thus suggesting that the AT is an important parameter in clinical assessments for such patients.

Cycling above rather than below lactate threshold is more effective for nitric oxide release and post-exercise blood pressure reduction in individuals with type-2 diabetes

“…These benefits would probably occur due to the higher metabolic and mechanical stress promoted by exercise at such intensity (Teodoro, Natali, Fernandes & Peluzio, 2010), since PEH is dependent of exercise intensity induced by the increase of the activity of the kallikrein-kinin system, and in consequence, a higher NO release (Pontes et al, 2008). Pharmacological treatments that increase the activity of the kallikrein-kinin system, and thus the production of NO, have shown efficacy in the treatment of individuals with hypertension and T2D (Moreira, Simões, Hiyane, Campbell, & Simões, 2007). On the other hand, non-pharmacological treatments, such as exercise, have also been characterized as good strategy to improve endothelial function (Rallidis et al, 2009), especially for not presenting collateral effects.…”

“…The present study hypothesized that both NO production and the occurrence of PEH, in individuals with T2D, would be dependent of exercise intensity domain. Thus, exercise performed above LT would elicit a higher NO release and a more significant PEH in individuals in T2D due to a higher metabolic and cardiovascular stress (Moreira, Simões, Hiyane, Campbell, & Simões, 2007;. Therefore, the aim of the present study was to analyze and compare the effects of different exercise intensities (above and below LT) on post-exercise BP and NO responses for individuals with T2D.…”

Métodos alternativos para estimar a velocidade da máxima fase estável de lactato em adultos jovens fisicamente ativos

“…This procedure is not feasible for participants enrolled in a training program and researchers often do not have the time or material needed for the tests. Therefore, investigators have tried to develop methods to optimize the estimation of MLSS [20][21][22] .…”

Treinamento de natação na intensidade do limiar anaeróbio melhora a aptidão funcional de ratos idosos

“…No presente estudo observou-se no grupo C aumento significativo do PC após quatro semanas (pré= 614,0±83,0 vs. pós=643,3±74,1; p<0,05), indicando que a falta de exercício físico sistematizado favorece o ganho de PC a curto e médio prazo, enquanto que o treinamento resultou em controle de PC durante o envelhecimento em ratos. Apesar de não termos avaliado os diferentes componentes da composição corporal na amostra estudada, especula-se que esse ganho de PC no grupo C esteja associado ao aumento da massa gorda, a qual apresenta inversa correlação com o LL em humanos (28) , expondoos aos diversos fatores de risco relacionados à obesidade. Por outro lado, o grupo de ratos idosos após quatro semanas de treinamento em natação apresentou manutenção do PC, podendo-se constatar diferença significativa (Figura 2-B) quando comparado o delta% de PC do grupo T com o grupo C (-0,8 ± 2,3 vs. 5,0 ± 2,8%; p < 0,05).…”